A great many apparatus are known for optically connecting two light conductors. In such apparatus, it is always decisive that the axial displacement or offset of both light conductors with respect to each other be as little as possible.
With measuring apparatus, it has become increasingly important to be able to connect a light conductor to the housing of the measuring apparatus. For this purpose, it is not only important that a good reproducibility of the positioning of the end of the light conductor be provided; however, it is also important that the spatial alignment of the axis of the light conductor be precise.
It is common that the ends of the light conductors be held in plug pins which are produced with high precision.
German patent No. 29 31 018 discloses a plug connector for connecting two light conductors wherein the plug pin is inserted into a receiving bore of a plug housing and is fixed therein. A longitudinal groove is machined into the wall of the receiving bore and a pressure piece is mounted on the opposite side for each plug pin. The pressure piece is pressed against the inserted plug pin by a sleeve nut threadably engaging the plug housing. The sleeve nut presses the pressure piece against the plug pin by means of a resiliently journalled pin and in this way fixes the plug pin against the edges of the longitudinal groove.
This known device makes possible a sufficiently precise fixation of two light conductors with respect to each other. However, it does not make possible a satisfactorily precise fixation of the axis of a light conductor which is connected to a measuring apparatus such as a diode-array spectrometer. This is especially the case when the light conductor is mechanically stressed outside of the plug connector.